A pickup truck drives through a flooded Highline Blvd just east of South Meridian Ave where several trees were also down after a tornado on the ground near El Reno Okla. just south of Interstate 40 on Friday May 31, 2013. (AP Photo/The World-Herald, Chris Machian) MAGS OUT; ALL NEBRASKA LOCAL BROADCAST TV OUT

Rescue personnel stand near overturned trucks in an industrial park after strong storms moved through the area Friday, May 31, 2013, in St. Louis. (AP Photo/Jeff Roberson)

People walk near an overturned truck in an industrial park after strong storms moved through the area Friday, May 31, 2013, in St. Louis. (AP Photo/Jeff Roberson)

Rescue personnel stand near overturned trucks in an industrial park after strong storms moved through the area Friday, May 31, 2013, in St. Louis. (AP Photo/Jeff Roberson)

Rescue personnel stand near overturned trucks in an industrial park after strong storms moved through the area Friday, May 31, 2013, in St. Louis. (AP Photo/Jeff Roberson)

Residents try to pass through a flooded intersection in Downtown Oklahoma City after multiple tornado's passed through Central Okla. on Friday May 31, 2013 in Oklahoma City. (AP Photo/Nick Oxford)

LAdy Vol softball players Melissa Davin and Tori Lewis make best of the situation as they hunkered down in an underground garage in Oklahoma City as a tornado passed through the area May 31, 2013.

Mike Strange/News Sentinel

OKLAHOMA CITY- MAY, 30: \sb during the game between the Tennessee Lady Vols and the Florida Gators on the first day of the Women's College World Series at ASA Hall of Fame Stadium in Oklahoma City, OK. The Lady Vols defeated the Gators 9-2. Photo By Andrew Bruckse/Tennessee Athletics

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Parts of Oklahoma City experience extreme flooding after multiple tornado's passed through Central Okla. on Friday May 31, 2013 in Oklahoma City. A violent storm formed over the prairie west of Oklahoma City late Friday afternoon, dropped a tornado in a suburb and rolled into the state capital as viewers brave enough to remain above ground watched on statewide television. (AP Photo/Nick Oxford)

This NOAA satellite image taken Friday, May 31, 2013 at 01:45 AM EDT shows fair weather across much of the Eastern US. Frontal boundary over the Midwest and Mississippi Valley with light to moderate rain and scattered thunderstorms, some being severe. (AP PHOTO/Weather Underground)